Experimental and laboratory report

Premature narrowing or closure of the foramen ovale

The incidence of children born with functional univentricular heart (UVH) and their prognosis presumably changed substantially in recent years. This is due to introduction of fetal echocardiography and potential termination of pregnancy (TOP) when UVH is diagnosed (UVH TOP), and to improvements in treatment. We aimed to explore changes in incidence, to estimate changes in survival, and to describe predictors of mortality in UVH patients.

Using a population-based design we identified all UVH cases in Denmark from 1977 to 2009.

703 UVH live births and 106 UVH TOP were identified. A dramatic decrease in birth incidence of UVH patients and a corresponding increase in UVH TOP was observed in recent years. Mean incidence rate of UVH (live births and UVH TOP) was 0.39 per 1000 births. In adjusted analysis survival improved significantly from birth era 1977–1989 to 1990–1999 (HR 2.65, 95% confidence interval (CI), 2.06–3.42) but not significantly from 1990–1999 to 2000–2009 (HR 0.77, 95% CI, 0.57–1.05). In the birth era 2000–2009, the lowest five-year survival was seen with hypoplastic left heart syndrome (HLHS) (18.8%), whereas the best survival was seen with tricuspid atresia (79.8%). Adjusted risk of death was 7.3 times higher in the HLHS group compared to the tricuspid atresia group (95% CI, 3.94–13.47).

This study demonstrates a dramatic decrease in birth incidence of UVH patients most probably due to a corresponding increase in UVH TOP. Despite survival improved after introduction of Fontan surgery, survival has not improved significantly during the last 20 years.

To assess the incidence and natural history of full-term neonates with interatrial shunt (IAS).

A follow-up study of 1389 neonates who received screening echocardiography between 2003 and 2006. Babies with IAS at 2 to 4 days of life underwent follow-up echocardiography at 2 to 4 months, 6 to 9 months and 12 to 15 months of age until closure of IAS.

The ratio of IAS was 68.3% initially. No significant demographic differences were identified between infants with and without initial IAS. Among 949 neonates with initial IAS, 84.5% infants had a left-to-right interatrial shunt, 13.5% had bidirectional shunt and 2% had predominantly right-to-left shunt. The persistence rate of IAS at 12 to 15 months of age was 3.8% (44/1166). The initial size of IAS ranged from 1.2 to 7.7 mm (4.3 ± 1.1 mm) detected by color Doppler flow mapping and cases were divided into three groups: small (≦5 mm), medium (5 to 8 mm) and large group (≧8 mm). There were 74.6% infants in the small group and 25.4% in the medium group initially. The neonates in the initial small group would always see their IAS close or else they would remain in the small group. Those in the final medium and large size groups always came from the initial medium group. The late closure rate of IAS was 93.9% of infants with initial IAS. The closure curves of initial small and medium sized groups were significantly different, and their late closure rates were 95.1% and 90.4%, respectively.

IAS was very common during early neonatal stage, but most cases would close after 1 year. The late closure rate of initial IAS was different if using a cutpoint of 5 mm.

Despite recent improvements in survival of patients with hypoplastic left heart syndrome, those with severe atrial level restriction continue to face higher rates of mortality. We sought to assess the impact of prenatal diagnosis and immediate intervention on the outcome of this high-risk population.

We performed a retrospective review of patients with hypoplastic left heart syndrome and restriction at the atrial level born between 1997 and 2006. Patients with an intact atrial septum or an interatrial communication less than 2 mm by color Doppler flow mapping on initial postnatal study, or evidence of obstruction to left atrial egress on fetal echocardiogram, were included. Patients were subdivided into two groups based on severity of obstruction.

Thirty-eight patients met inclusion criteria; 16 had the most severe form of anatomic obstruction (group 1), and 22 had a lesser degree of obstruction (group 2). Thirty-day cumulative survival for all was 68%: 38% for group 1 and 94% for group 2 (p = 0.001). Twenty-six of the 38 patients (68%) were prenatally diagnosed. Prenatal diagnosis did not improve initial hospital survival or cumulative survival for either group. Eight patients had progression of atrial level restriction from the first fetal study to the first postnatal study. Seven patients prenatally diagnosed with severe restriction underwent planned cesarean section followed by immediate surgical or catheter-based intervention, with only 2 survivors (28%).

Hypoplastic left heart syndrome with an intact atrial septum is a highly lethal condition despite prenatal diagnosis and immediate intervention at birth. Fetal intervention should be considered for these high-risk fetuses.

Patent foramen ovale (PFO) and atrial septal aneurysm (ASA) have a significant statistical relation to ischemic strokes in adults. We reviewed their prevalence in 106 echocardiograms of neonates. Although all normal neonates have PFO, only 4% had ASA. From fetal and neonatal echocardiograms, we conclude that ASAs are more likely to be caused by inadequate size of the PFO, but the ASA can act as a funnel, enhancing the chances of paradoxic embolization in the presence of a PFO. There is no convincing evidence that an ASA alone causes strokes in adults; the confounder is probably atrial fibrillation.